This invention relates to a transfer unit capable of transferring reaction vessels, dispensing tips and the like with a simple construction and more particularly to an automatic analyzing apparatus including such a transfer unit.
In the fields of the immunity analysis, chemicobiological analysis and the like, in recent years disposable dispensing tips and reaction vessels have been used in order to avoid errors in data due to carry-over and defective or failed washing. Such dispensing tips and reaction vessels are stored at particular locations and, as required, they are transferred by a transfer mechanism to predetermined positions (for example, dispensing tips after dispensation to discarding positions and reaction vessels to reaction tables or discarding positions) where the dispensing tips and reaction vessels are removed from the transfer mechanism.
On the other hand, recently there has been a strong need for the apparatuses of this kind to miniaturize and to reduce the manufacturing cost, and various attempts have been made to comply with these requirements. However, the miniaturization and low cost manufacture of the apparatuses have not been realized to a satisfactory extent because the transfer portion for tips and reaction vessels are imperative. Such prior art apparatuses have been disclosed in Japanese Patent Application Publication No. S59-33,212 and Japanese Patent Application Opened No. H6-18,534.
In the apparatus disclosed in the Japanese Patent Application Publication No. S59-33,212, recessed taking-off members are provided for mounting and dismounting tips, which may realize effective exchanging of tips. However, this apparatus suffers several disadvantages from the taking-off members required at all the mounting and dismounting locations, from complicated driving system due to three dimensional movements in longitudinal, transverse and vertical directions required in dismounting operations, and from spaces required to prevent the interference of the taking-off members with other mechanisms of the apparatus.
On the other hand, in the apparatus disclosed in the Japanese Patent Application Opened No. H6-18,534, removal of tips would be effected only by vertical movements to render the apparatus compact. With this apparatus, however, the complexity in construction of piping, rods, stoppers of rods, control mechanism for the stoppers and transfer mechanism has not been reduced or amended.
In general, robot arms have been known for gripping and transferring members such as reaction vessels, test tubes and the like. With such robot arms, however, the apparatus becomes bulky and control members such as driving motors or the like extremely increase, resulting in increased manufacturing cost which does not comply with the requirement in market.
In addition, with the apparatuses of this kind, it is desirable to detect or ascertain whether the tips or reaction vessels are securely held or removed in transferring operation. Incomplete holding and imperfect removal of these members will be caused by structural errors and operator's mishandling (has been forgotten to set tips or reaction vessels) and these incomplete holding and removal will in turn cause failure of the apparatus and incorrect data. In order to eliminate such difficulties, with the prior art apparatuses, light transmission sensors or image monitors are suitably arranged at particular positions to ascertain the holding and removal with the aid of light transmittance, reflectivity and image information. With such detecting means, however, particular spaces are needed for arranging the sensors, and arms must be once stopped or decelerated in the vicinity of the sensors so that detecting performance is deteriorated and time required for detection is increased.